Air conditioning apparatus



Mmmh i8, 194%. P. KUMROFF HTML @$35,023

AIR CONDI-TIONING APPARATUS Filed 001;. 2l, 1937 3 Sheets-Sheet l T INENTORS Marl is, 1941, MMROFF mm.. @5,923

AHI CONDITIONING APPARATUS P. KoMRor-'F Erm. v 2,235,023

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' AIR CONDITIONING APPARATUS 3 Sheets-Sheet 3 Filed Oct. 2l, 1957lyEN-rons Hwa aMeof-F 605567227. ff/W55??- l/ l l mA RNEY Patented Mar.18, 1941 Am CONDITIONING APPARATUS Paul Komrofi, New Rochelle, andRobert D. Lambert, New York, N. Y., assignors, by mesne assignments, toAmerican Radiator t Standard Sanitary Corporation, New York, N. Y., acor poration of Delaware Application October 21, 1937, Serial No.170,168

7 Claims.

Our invention relates to air conditioning apparatus, and moreparticularly to improvements in mechanisms for operating dampers whichcontrol the flow of air through such apparatus; the pres- 30, 1940, toMatson C. Terry.

The invention consists in the novel construction and combination ofparts, to be more fully described hereinafter, and the novelty of whichwill be particularly pointed out and distinctly claimed.

In the accompanying drawings, to be taken as a part of thisspecification, we have fully and clearly illustrated a preferredembodiment of ourv invention, in which drawings- Fig. l is a perspectiveview showing air conditionlng apparatus of the room-unit type in whichour improvement is embodied;

Fig. 2 is a transverse vertical sectional view through the apparatusshown in Fig. 1, the view being taken on the line 2-2 of Fig, l andbeing on an enlarged scale;

Fig. 3 is a fragmentary vertical section taken on the same plane as Fig.2` and showing the damper and its operating mechanism on an enlargedscale Fig. 'l is a fragmentary perspective view with parts in section,showing more clearly the details of the damper and itsoperating'mechanism;

Fig. 5 is a fragmentary plan sectional view taken on the line 5-5 ofFig. 6;

Fig. 6 is a view similar to Fig. 3, showing they relative position ofthe parts when the damper is automatically closed due to thenon-operation of an air conditioning means;

Fig. 7 is a fragmentary vertical sectional view taken on the line T-'Iof Fig. 5;

Fig. 8 is a view similar to Figs. 3 and 6, showing the relative positionof the parts when the damper is closed manually; and

Fig. 9 is a perspective view with parts in section, showing in detailthe structure of the composite lever for closing the damper when the airconditioning means is not operating.

Referring now in detail to the construction illustrated, andparticularly to Figs. 1 and 2, it will be observed that we have shownour improvement as embodied in an air conditioning unit of the typewhich is adapted to be installed in a room space and adjacent a windowopening in an outside wall thereof. The unit is lindicated in general bythe reference numeral III, and the 4window by the numeral I I.

'The unit I0 comprises a casing I2 having a room air inlet opening i3 inthe top wall and at the rear thereof, and an air outlet opening I4 inthe top wall and at the front thereof. The casing I2 is also providedwith an outdoor air inlet opening I5 in the upper and rear part thereof,which communicates with one end of a horizontally and rearwardlyextending outside air duct I6, and the outer end of the duct I6 beingopen and adapted to communicate with the outside atmosphere through theopening dened by a partially raised sash I1 of the window II,

Connecting the inlet openings I3 and I5 and the outlet opening I4, is aU-shaped passage I8 which is defined by the outer walls of the'casing I2and by a partition I9 depending from the top Wall of the casing I2between the inlet opening I3 and outlet Opening I4, and stopping shortof the bottom part of the casing so as to provide the return bend in thelower part of the passage.

Arranged in the upper rear part of the U- shaped passage I8 and adjacentthe inner open end of the duct I E, is a damper which is pivotallysupported, as indicated at 26,A between the inlet openings I3 and I5,and may be moved about its pivotal support between two extremepositions, one of which closes the inlet opening I5 and opens the inletopening I3, and the other of which closes the inlet opening I3 and opensthe inlet opening I5. As will appear ,more fully hereinafter, the damper25 may be positioned at any preselected point between these two extremepositions to proportion the amounts of room air and outside air enteringthe U-shaped passage I3 through the inlet openings I3 and I5respectively.

It is to be observed at this point that while the damper 25 has justbeen described as a proportioning damper, it is also correct to,consider the damper as closing and opening the outside air inletopeningl, and also to consider the opening I5 as a part of apassage 28connecting the outside atmosphere with the room, such passage 28 beingformed in part by the duct I6 and in part by the U-shaped passage I8. Inthe latter sense, the damper 25 opens and closes the passage 2B andthereby regulates the amount of air flowing through said passage 28.

Arranged below the damper 25 and across the passage 28 and U-shapedpassage I8, is a suitable iilter 3D which may be removably supported forready replacement and which serves toremove from the air iiowing throughthe passage 28 and its part I8, foreign particles, such as dust, dirt,pollen and the like. Arranged below the filter 30, is a cooling coil 3|,which when operating serves to lower the temperature oi .the

air flowing through the passage |8. The cooling coil may be of anysuitable construction. The one here shown is of the direct expansiontype through which a suitable refrigerant, such, for example, as sulphurdioxide or Freon, is circulated.

Arranged in the lower part of the U-shaped passage |8 is a motor-drivenblower unit 32 which provides for the positive flow of air through thepassage 28 and into the room through the outlet opening |4. Arrangedabove the blower 32 and just below the outlet opening |4 is a heatingdevice 33, here shown to be a conventional type of heating coil throughwhich a suitable heating fluid, such, for example, as hot water orsteam, is circulated.

In the warmer months of the year when the temperature of the outsideatmosphere is above the comfort range of the room space in which theunit I8 is located, the refrigerant is supplied to `the coil 3| and airflowing through the passage 28 and into the room is reduced intemperature so as to produce a desired comfort condition in the roomspace. During the colder months of the year when the temperature of theoutside air is below that of the room space, then the supply ofrefrigerant is shut oi from the coil 3| and heating iiuid is supplied tothe coil 33 andthe temperature of the air flowing through the passage 28is raised to a point where it will produce a comfortable condition inthe room space.

In accordance with the present invention, we have provided an improvedmechanism for operating the damper 25, whereby the amount of outdoor airflowing into the room through the unit I8 may be regulated. Regulationis required both in summer and in winter so that the room space will beproperly ventilated, and also so that the amount of ventilation can beproper adjusted with respect to the operation of the cooling or heatingunits to maintain a desired temperature condition in the room space.

Referring now to Figs. 2 to 9 inclusive of the drawings, it will benoted that the damper-operating mechanism is indicated in general by thereference character 35, and comprises a rst rod 36 which is pivotallyconnected at one end by a pin 31 to the damper 25 at points spaced fromthe pivot 26, so that the rod 36 and damper 25 will move together. Themechanism 35 also comprises a second rod 38, one end of which extendsforwardly through a vertical slot or opening 39 in a front vertical wallpart 40 of the duct I6, and the extreme forward end of the rod 38 has aknob 4| which may be grasped by hand for moving the rod lengthwise. Theother or rear end of the rod 38 extends rearwardly into the duct I6 andin the` same general direction as the first rod 36. As shown, the rods36 and 38 are arranged substantially parallel to one another. The secondrod 38 is supported for lengthwise movement by a suitable bracket 43having a vertical opening or slot 44 therein. The forward end of the rodmoves lengthwise through the opening 39.

At the forward end of the rod 38 and in the underside thereof isprovided a series oi spaced notches 45, and at the bottom of the opening39 and on the inside surface of the wall part 48 is fixed a plate 46which extends slightly above the bottom of the opening 39 and is adaptedto engage any desired one of the notches 45 and thereby secure or lockthe rod 38 against lengthwise movement at any desired preselectedposition. When it is desired to move the rod 38 lengthwise to a newVposition, the forward end of the rod may be simply raised by graspingthe knob 4| and the particular notch 45 disengaged from the plate 46,and the rod'may then be moved at will forwardly or rearwardly. Theopening 39 is of suilcient height to permit the necessary clearancebetween the notches 45 and plato 4l when the rod is lifted.

The mechanism 35 also comprises a link 58 connecting the first andsecond rods 36 and 38 at the rear ends thereof. The link 50 is pivotallyconnected to the rear end of the second rod 38 by a suitable pin 5|, andis pivotally connected to the rear end of the rod 36 by a pin 52extending transversely through a slot 53 formed in the first rod 36and-extending lengthwise thereof. A compression spring 54 engaging atone end an abutment formed by a transverse pin 55 in the rear end of therod 36, and engaging at the other end the lower part of the link 58,serves to hold the pin 52 tightly against the forward end of the slot 53(see Figs. 3 and 4). nection provided by the pin 52, slot 53 and spring54, will appear more fully hereinafter.

Fixed to the connecting link 58 and projecting forwardly at the sidethereof adjacent the damper is an abutment 51 which is adapted to engagethe lower end of an adjusting screw 58 which, functionally, is a part ofthe rod 38. The

screw 58 extends through a threaded opening in the rod 38 and serves tosecure the proper positional relationship between parts. When theabutment 51 is in engagement with the screw 58, relative movement isprevented between the link 50 and rods 36 and 38, should the rod 38 bemoved in a damper-closing direction, and should the rod 36 be moved in adamper-opening direction.

The mechanism 35 also includes a tension spring 59 connecting the rods36 and 38 at points spaced forwardly from the link 58. The spring 59 isso arranged that it functions to urge the rod 36, damper 25 and link 50forwardly with respect to the rod 38, and thereby effect engagementbetween the abutment 51 and the screw 58 which, as stated, is afunctional part of the rod 38. This is made possible, due to the factthat the spring 59 and link 58 are inclined toward one another in thedirection extending toward the rod 36. It will be apparent that as thespring 59 holds the abutment 51 tightly against the screw 58 of rod 38,the Iparts are held together as a unit and the damper may be moved toany preselected position by the manual lengthwise movement of the rod38.

Figs. 2, 3 and 4 show the relative position of parts when the rod 38 isadjusted to position the damper so as to partially open the inletopening I5. Fig. 8 'shows the relative position of the parts when therod 38 is adjusted to close the damper 25. the forward notch 45 on therod 38 engages the plate 46, and that the pin 52 is spaced from theforward end of the slot 53. The lpurpose of the .lost-motion connectionprovided by the pin 52,

slot 53 and spring 54, is to permit the rod 38 to be moved inwardlybeyond the point where the damper 25 is closed and against the force ofthe spring 54. The spring 54 will then serve to hold the damper tightlyin its closed position. This construction is advantageous because atight closing of the damper may always be assured without the necessityof extreme accuracy The purpose of the lost-motion con- In Fig. 8, itwill be observed that assauts in. manufacture, assembly and adjustmentoi' the rods 36 and 38 and the link 55.

In accordance with the present invention, we also provide as a part ofthemechanism 35, a means which acts in response to an operatingcharacteristic of an air conditioning element for automatically closingand opening the damper 55 and thereby regulating the amount of outdoorair iiowing through the passage 25. In the illustrated embodiment of ourinvention, we have shown this means as including a thermostat 55 whichacts in response to the temperature of the air flowing from the heatingcoil 33 to control the operation of a heat motor i, the latter bcingoperatively connected to the damper by a suitable chain 62 (see Fig. 5).

The operation of the means just referred to is such that when' thetemperature of the air passing from the heating coil 33 falls below apre-A determined minimum, the heat motor 6l operates to pull the chain52 taut and close the damper 25 against the force of the spring 55. Theheat motor 5l will hold the damper tightly closed until the temperatureof the air owing from the coil 33 rises above the aforementionedpredetermined minimum. When the latter occurs, the heat motor acts torelease the damper 25 and the spring 53 returns the damper to a positiondetermined by the preselected secured position of the rod 33. v

The heat motor is enclosed within a housing 5ft supported by a wall ofthe duct I6, and comprises a cylinder 65 secured to a wall 65 of thehousing 64, an expansible metallic bellows 6l located within thecylinder 65 and fixed at one end to the wall 55, a rod 63 xed at one endto the movable end of the bellows 6l and the other end extendingthroughan opening B5 in the wall 55, and a compression spring 15encircling the rod 55 and abutting at one end the wall 65 and at theother end the movable end of the bellows (see Figs. 5 and 7). l f

The heat motor 5l also comprises a composite lever 'l l which isfulcrumed intermediate its ends as indicated at 'l2 and is pivotallyconnected at one end to the outer end of the rod 68 (see also Fig. 9).The other end of the lever is connected by the exible chain 52 with thedamper 25. The compositelever ll comprises an element 'l5 including aweb portion 'I6 and lateral right-angle flanges ll.- The flanges 'ilreceive a pin 'l5 which forms a part of the iulcrum l5, and is supportedfrom the wall 55 by spaced brackets l5. The outer end of the rod 55 issecured by a suitable pin 55 to one of the ilanges ll. The compositelever also comprises an element 5l pivotally mounted on the iulcrum -pin"l5, and secured to the element 'l5 by a pin 55 passing through theelement 5l and one of the ilanges 'lll of the element l5. The flexiblechain 55 is connected at one end to the outer end of the element 5l, andis connected at the other end to the pin 5l carried by the damper 55.

The heat motor also comprises an electrical heating element 55encircling a small chamber 55 positioned in the housing 55, and thechamber is connected toI the cylinder 55 by a small tube 5l. The chamber55, tube 5l' and the space in the cylinder 55 outside oi `the bellows5t, are adapted to be filled with any suitable expansible i'luid, such,for example, as ethyl chloride, sulphur dioxide, ether, or the lilre.

rli'he electrical heating element 55 is connected in an electrical.circuit with the thermostat 55 by conductors dit. The 'thermostat may beoi' any suitable construction, depending upon the type of controldesired. The one here shown operates to close the electrical circuitwhen the temperature of the air engaging the thermostat is above apredetermined point, and to open the circuit when the temperature of theair falls below the predetermined point.

When the thermostat 65 closes the electrical circuit, the heatingelement 55 is energized, which results in the vaporization of the iluidin the chamber 86, tube 8l and cylinder 65, and in the compression ofthe bellows 6l. As the bellows is compressed, the rod 6B moves outwardlyof the housing 65 against the force of the cornpressicn spring 'l5 andmoves with it the lever 'll in a direction to put slack in the chain 62and permit the spring 59 to move the damper to the position preselectedby hand adjustment of the rod 33. When the thermostat 65 opens theelectrical circuit, the element 85 is deenergized. This will result inthe contraction of the expansible fluid in the chamber B6 and in thecompression spring moving the bellows 5l back to its fully extendedposition, and moving with it the rod B8 and lever 1l and pulling thechain B2 taut and closing the damper 25.

In the embodiment illustrated, the normal con-y dition is the one Wherea heating iiuid is supplied to the coil 33. As stated previously, whenheat is in thev coil 33, the thermostat 6I] is closed and the heatingelement 55 is energized and the damper 25 opened. This position is theone `shown in Figs. 2, 3 and 4 of the drawings. With the parts in thisposition, the damper 25 may,

be moved to any new position by simply moving the rod 38 forwardly orrearwardly by hand in the manner previously explained. `Should thesupply of heating uid be shutioi for any reason, the thermostat 55 willopen the circuit, deenergize the heating element 55, and close thedamper in the manner before explained. lflhe closed position is shown inFigs. 5 and 6 of the drawings. It will be noted from an examination ofFig. 6 that the abutment 5l has been moved away from the screw 55 of rod35. With the heating element 55 deenergized, the damper cannot beopened. However, the position to which the damper will move when theheating element again becomes energized, can be changed by moving therod 33 in or out in the manner explained previously. This is permitted,due to the spring and link connection between the rod 35 and the rod 35.

From the above, it is apparent that we have provided a mechanism whichpermits the damper to be accurately adjusted by hand to any preselectedposition, and which at the same time provides for the automatic closingof the damper in response to changes in an operating characteristic ofan air conditioning element. While we have shown the mechanism 55 asoperating in response to the temperature of the heatingcoil it is to benoted that the invention is not limited in all oi its aspects to thisparticular arrangement; ior, insofar as the broader aspects of theinvention' are concerned, the mechanism 55 may operate in response to anoperating charto mean any condition which reflects the operation of theair conditioning means; that is to say, any condition which indicates orshows whether or not the air conditioning means is operating, or itsdegree of operation, or the air conditioning effect produced by theairconditioning means because of its operation. One example of anoperating characteristic of the air conditioning means would be thetemperature of the air leaving the heating coil 33, as described above.The temperature of the air leaving the coil changes with the heat outputof the coil and thereby indicates whether or not the coil is operating.Other examples of operating characteristics of an air conditioning meanswould be the surface temperature of a heating or cooling coil; thetemperature of a heating or cooling medium fiowing through a heating orcooling coil; the rate of fiow of a cooling or heating medium through acoil; and the pressure of the fluid inside of a coil as in the case of asteam coil and in the case of a refrigerant in a cooling coil.Obviously, any operating characteristic of the air conditioning meansmay be used as a source of control for the opening and closing of thedamper 25, without departing from the intended scope of the presentinvention.

It is advantageous to have a damper which may be adjusted at will toregulate accurately the amount of outdoor air fiowing into a room whichis being air conditioned. In the Winter time, the amount vof outdoor airentering the room has a direct effect on the ability of the heating coilto maintain a desired temperature in the room, and should the heatingcoil fail to operate, it would be desirable to close the outdoor airinlet so that the comfortable condition could be maintained in the room,and so as to prevent cold f drafts. Furthermore, continued flow of coldoutside air might damage the unit by freezing the water-filled partstherein.

The apparatus described above can perform these desired functions in anadmirable manner. The position of the damper may be easily and quicklyadjusted, and the mechanism for posi- .tioning the damper does notinterfere in any way with the automatic closing and opening `of thedamper when required. The two rods 36 and 38, the link 50, with theabutment 51 and the tension spring 59, make the performance of thesefunctions possible.

What we claim and desire to secure by Letters Patent of the UnitedStates is:

1. In air conditioning apparatus, means defining an air passage; meansfor changing the condition of the air flowing through said passage; adamper movable between closed and open positionsfor regulating the flowof air through said passage; a first rod connected at one end to thedamper and movable lengthwise with the damper; a second rod extending inthe same general direction as said first rod and spaced therefrom andmovable lengthwise by hand; means for securing said second rod againstlengthwise movement at any one of a plurality of positions; a

connecting link pivoted at oneA end to the first rod and pivoted at itsother end to the second rod; abutment means on said link and adapted ,toengage one of said rods and prevent relative movement therebetween whensaid first rod is moved in' a damper-opening direction and when mentinto said engagement with the ro'd so that the first and second rods andconnecting link are normally held together for movement as a unit foradjusting the position of the damper; and means acting in response tochanges in an operating characteristic of said air conditioning meansfor moving said damper in a closing direction against the force of saidurging means upon a givenreduction in output of said air conditioningmeans.

2. 1n air conditioning apparatus, means defining an air passage; meansfor changing the condition of the air flowing through said passage; adampermovable between closed and open positions for regulating the ow ofair through said passage; a first rod connected at one end to the damperand movablelengthwise with the damper; a second rod extending in thesame general direction as said first rod and spaced therefrom andmovable lengthwise by hand; means for securing said second rod againstlengthwise movement at any one of a plurality of positions; a connectinglink pivoted at one end to the first rod and pivoted at its other end tothe second rod; abutment means on said link and adapted to engage one ofsaid rods and prevent relative movement therebetween when said first rodis moved in a damper-opening direction and when said second rod is movedin a damper-closing direction; means for constantly urging said abutmentinto said engagement with the rod so that the rst and second rods andconnecting link are normally held together for movement as a unit foradjusting the position of the damper; and means for closing said damperagainst the force of said urging means when said condition-changingmeans is not operating and permitting said urging means to open saiddamper tov a point determined by the preselected secured position ofsaid second rod when the condition-changing means is operating.

3. In air conditioning apparatus, means dening an air passage; means forchanging the condition of the air flowing through said passage; a dampermovable between closed and open psitions for regulating the flow of airthrough said passage; a first rod connected at one end to the damper andmovable lengthwise with the damper; a second rod arranged in spacedsubstantially parallel relation with the rst rod and movable lengthwiseby hand; means for securing said second rod against lengthwise movementat any one of a plurality of points; a connecting link pivotallyconnected at its ends to said first and second rods, respectively;abutment means on the side of said link which is adjacent said damper'and adapted to engage said second rod and prevent relative movementtherebetween when said first rod is moved in a damper-opening directionand when said second rod is moved in a damper-closing direction; atension spring connecting said first and second rods at points spacedfrom said link and between the link and damper and extending in aninclined direction with respect to said rods so as to constantly urgesaid abutment means into engagement with Said second rod, and so thatthe first and second rods and connecting link are normally held togetherfor movement as a unit for adjusting the position of the damper; andmeans for closing said damper against the force of said spring when saidcondition-changing means is not operating and permitting said Spring toopen said damper to a point determined by the preselected secured p0-sition of said second` rod when the conditionchanging means isoperating.

4. In air conditioning apparatus, means defining an air passage; meansfor changing the condition of the air flowing through said passage; apivoted damper movable between open and closed positions lor regulatingthe flow of aifr through said passage; a first rod pivotally connectedat one end to said damper at points spaced from the pivotal axis andextending away from the latter in a direction transverse to the pivotalaxis so that the rod may be moved lengthwise for opening and closing thedamper; a second rod spaced from said first rod and extending frompoints adjacent said damper in the same general direction as said firstrod; means providing for lengthwise movement of said second rod by handand for securing said second rod against lengthwise movement at any oneof a plurality of positions; a connecting link pivoted at one end to therst rod and pivoted at its other end to the second rod; abutment meanson said link andadapted to engage one of said rods and prevent relativemovement therebetween when said rst rod is moved in a damperopeningdirection and when said second rod is moved in a damper-closingdirection; means for constantly urging said abutment into saidengagement with the rod so that said first and second rods and saidconnecting link are normally held together for movement as a unit foradjusting the position of the damper; and means for closing said damperagainst the force of said urging means when said condition-changingmeans is not operating and permitting said urging means to open saiddamper to a point determined by the preselected secured position of saidsecond rod when the condition-changing means is operating.

5. ln air conditioning apparatus, mean denning an air passage; means forchanging the condition of the air owing through said passage; a dampermovable between closed and open positions for regulating the flow of airthrough said passage; a first rod connected at one end to the damper andmovable lengthwise with the damper; a second rod extending in the samegeneral direction as said flrstrod and spaced therefrom and movablelengthwise by hand; means for securing said second rod againstlengthwise movement at any one of a plurality of positions; a connectinglink pivoted at one end to the first rod and pivoted at its other end tothe second rod; abutment means on said link and adapted to engage one ofsaid rods and prevent relative movement therebetween when said first rodis moved in a damper-opening direction and when said second rod is movedin a damper-closing direction; a tension spring connecting said rods atpoints spaced from said connecting link and extending in an inclineddirection with respect to said rods so as to constantly urge said firstrod, connecting link and damper to move in a damper-opening directionand eiect said engagement between the abutment means and one of saidrods, whereby movement of said second rod by hand will result in saidlink, said rst rod and said damper moving therewith as a unit; and meansconnected to said damper for closing the latter against the force ofsaid spring when said conditioning means fails to operate and permittingsaid spring to return the damper to the position determined by thepreselected secured position of said second rod when said condition-ling means operates again.

6. In air conditioning apparatus, means dening an air passage; means forchanging the condition of the air owing through Vsaid pas sage; a dampermovable between closed and open positions for regulating the flow of airthrough said passage; Iirst and second rods arranged in spacedsubstantially parallel relation; said rst rod being connected at one endto said damper for lengthwise movement therewith and said second rodbeing movable lengthwise by hand to any one of a plurality of positions;means for securing said second rod against lengthwise movement at any ofsaid positions; a link connected at its ends to said first and secondrods, respectively, a tension spring also connecting said rods and atpoints spaced from the link and at the damper side of the latter;abutment means on said link and on the side thereof adjacent said springand adapted to engage said second rod; said link and said spring beinginclined toward one another in the direction extending toward said firstrod so that the spring tends to hold said abutment means against saidsecond rod and so that normally, said rst rod, link and damper may bemoved manually as a unit with said second vrod for positioning thedamper; and means for closing said damper against the force of saidspring when said condition-changing means is not operating and permitting said spring to open said damper to a point determined by thepreselected secured pol sition of said second rod when theconditionchanging means is operating.

7. In air conditioning apparatus, means defining an air passage; meansfor changing the condition of the air flowing through said passage; adamper movable between closed and open positions for regulating the owof air through said passage; a first rod connected at one end to thedamper and movable lengthwise with the damper; a second rod extending inthe same general direction as said first rod and spaced therefrom andmovable lengthwise by hand; means for securing said second rod againstlengthwise movement at any one of a plurality of ,separate and distinctpositions; a connecting link; a pivotal connection between one end ofsaid link and one of said rods and'a second pivotal connection betweenthe other end of said link and the other of said rods; abutment means onsaid link and adapted to engage one of said rods and prevent relativemovement therebetween when said first rod is moved in a damperopeningldirection and when said second rod is moved in a damper-closingdirection; means for constantly urging said abutment into saidengagement with the rod so that the first and second rods and connectinglink are normally held together for movement as a unit for adjusting theposition of the damper; one of said pivotal connections comprising a,lost-motion connection including a spring for taking up the lost motionand being so constructed that said second rod can move after the damperis closed in a damper-closing direction and against the force of thespring, and can be secured at a position past the point Where the damperis closed with the spring holding the damper tightly closed; and meansfor closing said damper against the force of said urging means when saidcondition-changing means is not operating and permitting said urgingmeans to open said damper to a point determined by the preselectedsecured position of said second rod when the condition-changing means isoperating.

PAUL KOMROFF. ROBERT D. LAMBERT.

